The factorial of a number is the product of all the integers from 1 to that number.

For example, the factorial of 6 (denoted as 6!) is 1*2*3*4*5*6 = 720. Factorial is not defined for negative numbers and the factorial of zero is one, 0! = 1.

Source Code

# Python program to find the factorial of a number using recursion
def recur_factorial(n):
"""Function to return the factorial
of a number using recursion"""
if n == 1:
return n
else:
return n*recur_factorial(n-1)
# Change this value for a different result
num = 7
# uncomment to take input from the user
#num = int(input("Enter a number: "))
# check is the number is negative
if num < 0:
print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
print("The factorial of",num,"is",recur_factorial(num))

Output

The factorial of 7 is 5040

Note: To test the program, change the value of num.

Here, the number is stored in num and use recursive function recur_factorial() to compute the product up to that number.